Spring cover apparatus



Nov. 20, 1934.

v. w. PETERSON 1,981,189

SPRING COVER APPARATUS Filed March 25. 1932 s Sheets-Sheet i fizz/era??? Vz'cZar I/ 2 956725072, MMW -M Q Nov. 20, 1934. v, w, PET R 1,981,189

SPRING COVER APPARATUS Filed March 23, 1932 :5 Sheefs-Shet 2 fry/9222 6 @WMM MMf Patented Nov. 20, 1934 UNITED STATES SPRING COVER APPARATUS I Victor W. Peterson, Chicago, Ill., assignor to Hannifin Manufacturing 00., Chicago, Ill., a

corporation of Illinois Application March 23, 19%.2, Serial No. 600,669

16 Claims.

This invention relates to spring cover applying apparatus, and among other objects aims to provide improved apparatus of this character by which spring covers may be quickly and easily applied. I

The nature of the invention may be readily understood by reference to one construction embodying the invention and shown in the accompanying drawings.

In said drawings:

Fig. 1*is a perspective view (taken from the front) of the illustrative apparatus showing a spring cover in an intermediate stage of application;

Fig. 2 is a fragmentary front elevation of the apparatus wherein the application of the spring cover (only one half of the spring being here shown) has advanced one stage beyond that illustrated in Fig. 1;

Fig. 3 is a transverse section-taken on the plane 3--3 of Fig. 2 (and on a scale somewhat larger than that of Fig. 2) showing one of the later stages in the application of the spring cover; V

Fig. 4 is .a-transverse section taken on the plane 44 of Fig. 1 (and on a scale "somewhat enlarged relative to that of Fig. 1) showing the closing or beading apparatus for completing the application of the spring cover by connecting 33 the cover elements together;

Fig. 5 is a sectional view, somewhat diagrammatic in character of the relation of spring and spring cover atthe initial stage of application;

Fig. 6 is a similar view showing the spring 85 and spring cover elements;

Fig. 7 is a view (on a reduced scale) showing the relationship of the apparatus to the spring cover just prior to the lateral bending of the spring cover by the apparatus; and

Fig. 8 is a similar view (corresponding to that of Fig. 3) showing the apparatus after the sides of the spring cover have been brought into en gagement with the spring.

The invention is here shown embodied in a machine for applying sectional sheet metal covers to curved automobile leaf springs and the like. The illustrative metal cover comprises a plurality of relatively movable metal sections 10 01. channel shape adapted to embrace the spring,

and a top element 11 applied to the sections after application of the latter to complete the enclosure of the spring (see Figs. 5 and 6). The sections being relatively movable, they may relatively adjust themselves with the flexure of the spring. In the present case, adjacent sections are hingedly connected together at the points 12 by appropriate rivets or other fastening means, thus preventing complete separationof the sections though not interfering with-... their relative movement. 0

To facilitate application, the sides 13 of the sections. are flared and'after application to the spring, are brought together (see Figs. 7 and 8) for application of the cover element 11 to the grooved or flanged margins 14. The cover 5. 11, as here shown, is continuous for the length" of the connected sections, extending in this case approximately half the length of the spring, and is provided with complementary flanged margins 15 which enter the grooves 14 (see Fig. 3), later 7 to form connecting seams 16. Before application of the spring cover, it is desirableto apply lubricant to the spring. This is advantageously effected, as-here shown. by coating the spring with graphite grease and then covering the same with a canvas or similar wrapping 1'7.

To facilitate application of the spring cover, particularly the cover element 11, the spring is engaged at its ends and in the middle (or in the region in .which the spring is to be connected to 0 the chassis) by relatively moving devices which apply forces to straighten the spring. As here shown, the ends of the spring are connected to swinging arms 18 hinged at 19 at their lower ends to the base 20 and carrying at their upper 35- ends removable pins or bolts 21 adapted to pass through the respective eyes of the spring. The freedom of the ends of the arm to swing together and apart, adapts the apparatus for a large variety of spring lengths. The ends of the arms 18 are constructed and arranged to receive a variety of spring widths.

The spring is here shown placed in the apparatus with its concave side up and is engaged at an intermediate point by a movable plunger 22 which flexes the spring upwardly until the uppermost or main leaf (which is generally the longest leaf of the spring), is substantially straight. The plunger is here shown actuated by an air cylinder 23 into which air is admitted and from which it may be exhausted (to permit return of the plunger) by an appropriate control valve (not shown). The stroke of the plunger is given sumcient range to straighten the main or upper leaf spring regardless of variations in aggregate spring thickness. Variation in thickness or number of leaves of the spring is compensated for by making the saddle 24 which engages the spring and is carried by the plunger, shallower or deeper (by the use of the levers.

shims) as the case may require. When the saddle is thus adjusted to the thickness of the spring, the plunger will automatically flex the spring until the upper leaf is substantially straight.

When the spring is thus straightened, the cover elements may be applied. The channel shaped cover sections 10 are here shown temporarily held in place by a platen 25 (one for each half of the spring) inclined in conformity with the inclination of the lower faced the spring. The platen is held in position and automatically adjusted to the proper inclination by a pair of plungers 26 to which it is hinged at 27. The plungers are actuated by small air cylinders 28 into which air is admitted and from which it is exhausted by the tubes 29 controlled by an appropriate valve (not shown). The diameter of the air cylinders 28 is made small so that with the use of air pressures commonly employed in the shop, be merely sufllcient to hold the cover elements in place and particularly will not be great enough to exert any bending pressure on the spring to distort it during the application of the cover and particularly the cover top 11. The platen and the plungers 26 thus come to rest when the upward movement of the platen is arrested by contact with the spring, the platen accommodating itself to the inclination of the lower face of the spring.

The flared sides 13 of the cover sections are brought into position by devices which exert a laterally directed force which has no component to disturb or flex the spring. As here shown,

the laterally directed forces are applied by lever arms 30 pivoted at 31 and moving at the com-' pletion of their travel in a horizontal direction or a direction perpendicular to the side face of the spring. The forces thus applied being normal to the spring have no, component which would flex or otherwise disturb the spring.

The lever arms are moved into and out of operative position by plungers 32 (one for each half of the spring) carrying plates 33 to which the lever arms are connected. Control of the plunger air cylinders is effected by appropriate air'valves, not illustrated. .As here shown, the lever arms are of bell crank form with the extremities of their arms 34 connected by links 35 to the plates. In this case, the lever arms are arranged in pairs, each pair carrying a plate in the form of an angle arm 36 removably connected thereto and which serves as the element for engaging the flared sides 13 of the cover sections. To accommodate springs of different widths, it is merely necessary to adjust the distance between the faces of the angle plates by the use of shims or other means so that when lying parallel to the side faces of the springs they will be separated by the proper distance. Small variations in spring widths require no adjustment of the angle plates 36 as will presently appear. I

The lever arms are actuated in the present instance by the upward movement of the plunger 32 in cooperation with the limit rods 3'? whose enlarged ends 38 eventually engage the under face of the stationary plate 39 and arrest the further upward travel of the pivot points 31 of As illustrated in Figs. 7 and 8, continued upward movement of the plate 33 causes the opposite pairs of lever arms 30 to move together and carry the flared sides 13 of the cover sections into engagement with the side faces of ,plunger 32.. Limit rods 43 the pressure exerted by the platen will the spring by a laterally directed force which does not flex the spring. The enlarged ends 38 on the rods may be provided by adjustable nuts which may be adjusted longitudinally on the rods to initiate the closing movement of the lever arms at the proper point with reference to the spring. As here shown, pairs of rods 3'7 are employed, each pair carrying a pivot rod 40 which forms the pivot 31 for the arms 30. To avoid binding of the rods during their upward and downward travel they operate within short sections of tubular guides 41 bolted to the stationary plate 39. Springs 42 are interposed between the movable plate 33 and the lever arms 30 to cause the latter to rise and thus separate upon the downward movement of plate 33 and its which pass through the springs 42 and plate 33 and are connected to the rods 40, carry nuts on their lower ends to engage the under face of plate 33 to limit the upward or separating movement of the lever arms under the action of springs 42.

When the sides of the cover sections are brought into place, cover top 11 is applied by seating one of the flanges 15 in its groove 14, thus providing enough clearance to allow the opposite flange 15 to pass over the edge of the cover sections and into its groove 14. In this connection it should be noted that the top cover and the cover section grooves 14 are so designed that under the pressure of the plates 36 the grooves are brought sufficiently close together to allow the application of the top cover 11 as aforesaid. This application is easily effected since the grooves 14 in the cover sections are straight and require no flexing of the flanged (and therefore relatively rigid) top cover 11. As appears from the foregoing, once the apparatus has been adjusted to flex the spring so that the grooves 14 are straight, subsequent operations on the cover will not disturb this alinement. Application of the top cover 11 by sliding the same longitudinally into the grooves 14 is impracticable since the end edges of the individual sections 13 are likely to present obstacles. The use of a hammer to drive on the top under these conditions almost invariably results in bending or distortion of the metal.

' After application of the top'cover as aforesaid, pressure is applied to bend the interlocking flanges together to form interlocking seams '16. This operation is advantageously effected in the present case by movable air hammers which may be made to travel at a uniform rate along the spring so as neatly and uniformly to form the seams. The air hammer is here shown in the form of a cylinder 44 mounted so as to be vertically slidable toward and away from the work in a cylindrical housing 45 which is externally threaded and screwed into a carriage movable on rollers 46 on the horizontally extending'tracks 47. The cylinder 44 constitutes the air hammer and in the present case carries on its interior a hammer element 48 which also serves as the valve for actuating the hammer. When air is applied through the air connection 49 the air hammer cylinder 44 travels downwardly under the pressure of the air, compressing spring 50 which raises the hammer when the air is cut oil. The hammer thus descends until the die or "set 51 engages the work and is moved inwardly a shortidistance by the continued downward movement of cylinder 44. The former movement is transmitted through the stem 52 of the set to the hammer element 48 which is moved upwardly until its enlarged upper end 53 uncovers the air inlet ports 54. These ports being connected with the air supply through the air inlets 55 and the annular passage 56 around the hammer, admit air and thus apply pressure to the under face of the shoulders 57 of the hammer, thus causing it to rise until the ports 58 inside the hammer register with ports 54. Ports 58 being in communication through the passa 59 with the upper face of the hammer, thus serve to apply air pressure above the hammer and throughout its full diameter to drive the hammer downwardly upon its power stroke to deliver its blow to the stem 52 of the set." Simultaneously the ports 58 come into register with the exhaust ports 60 which are connected by passages 61 with the exhaust outlets 62 in the lower edge of cylinder 44. The cycle is repeated so long as'the stem 52 of the set remains in its inner position in the cylinder 44. If it is permitted to move downwardly or outwardly either by raising of the hammer from the work or otherwise, the hammer 48 is permitted to move downwardly until the cylindrical portion 53 closes the inlet ports and stops the hammer.

With the foregoing arrangement, the cylinder 44 is automatically held against the work and 18 caused to follow the work under the pressure of the air upon the top 63 of the cylinder. Thus the workman is not obliged to devote any atten tion to maintaining the hammer in operative en-' gagement with the work; the workman can devote his entire attention to moving the hammer uniformly along the work so that the metal is uniformly treated and the work will not be marred by concentration of blows in one spot as would occur if the workman applied an ordinary air hammer to the work and was required both to maintain it in operative relation to the work and to move it along the work. The irregular or intermittent longitudinal movement of the hammer which would inevitably ensue in the latter case, would cause an objectionable unevenness in the metal and in the seams 16.

Upon the closing of the air valve the cylinder is immediately elevated under the action of spring 50 carrying the set out of contact with the work. Upon the latter movement, the set again falls to its outer position and the hammer is thus permitted to travel outwardly until the surface 53 closes ports 54, in which position the hammer will remain (even though the air be turned on again) until the set engages the work and moves the hammer up to uncover the ports. The movement of the set is limited by the reduced portion 65 on its shank into which the screw 64 extends without, however, engaging the stem 52 to interfere with the movement of the set. A stop member 66 is fastened to the lower end of the hammer to limit the downward movement of the cylinder 44 with relation to' its holder 45.

The range of movement given the cylinder 44 is sufllcient to permit it to clear the eye of the spring so that it may be moved beyond the ends of the arms 18. In the present case, to increase production, one hammer is shown for each half of the spring. Upon completion of the application of the cover, the air valves controlling the plungers 22, 26 and 32 are opened, permitting the plungers to fall and allowing the spring to resume its normal curved position. Thereupon the pins 21 are withdrawn from the eyes of the spring and the spring removed from the apparatus. It will be noted that'compression springs 67 are associated with the arms 18 so as nor mally to force the arms back and prevent their 3 falling upon the apparatus when not in use.

In Fig. 4 the device is shown with air applied" and in extended position with the set 51 in its outer position in which it remains until pressed against the work. I

, When the cover has .thus been applied all accessory mechanisms maybe withdrawn to a remote position and they remain so during the insertion of another spring, thus facilitating this operation as well as those of applying the lubricant and fabric wrapping and the insertion of the metal cover elements 10 into operative position. In the present case, the plates 36 are withdrawn after the top 11 has been applied but before the seam forming operations. This capacity for quick and complete withdrawal from the spring position enormously reduces the time required for applying the covers.

Obviously the invention is not limited to the details of the illustrative construction since these may be variously modified. Moreover, it is not indispensable that all features of the invention be used conjointly since various features may be used to advantage in different combinations and sub-combinations.

Having described my invention, I claim:

1. Spring cover applying apparatus comprising in combination spring straightening means, clamping means operated independently of the spring for applying forces normal to the sides of the spring to cause the cover to embrace the spring, and means for moving said clamping means away from the spring.

2. Spring cover applying apparatus comprising in combination spring straightening means, a track extending longitudinally of said spring, a closing tool movable on said track for closing the cover on said spring, and means for automatically moving said tool toward and away from said spring.

3. Spring cover applying apparatus comprising 120 in combination spring straightening means, clamping plates movable laterally toward and away from the sides of the spring, a support for said plates movable to carry said plates into and out of operative position, and means actuated by the movement of said support toward the spring to move said plate laterally to apply force normal to the sides of the spring.

4. Spring cover applying apparatus comprising in combination spring straightening means, a pair of independent plungers, a platen for holding a spring cover against the under face of the spring and pivotally connected to and carried by said plungers, and means for applying a small force to said plungers sufiicient to operate said platen but insuflicient to exert any substantial flexing force upon the spring whereby said platen assumes the angle of the under face of the spring.

5. Spring cover applying apparatus comprising in combination spring straightening means, devices for applying a cover to said spring, a trackway extending longitudinally of the spring, and an air hammer carried on said trackway and movable toward said spring for closing the seam on the spring cover.

6. Spring cover applying apparatus comprising in combination spring straightening means, devices for applying a cover to said spring, a trackway extending longitudinally of the spring, 150

an air hammer carrier including a cylinder travelling on said trackway, and a cylindrical air hammer operating in said cylinder and movable toward and away from said spring whereby the air hammer will remain in operative engagement with the spring as the same is moved longitudinally on said trackway.

7. Spring cover applying apparatus comprising in combination spring straightening means, an air operated plunger carrying a pair of plates for engaging the opposite sides of the spring cover, levers upon which said plates are mounted, said plates being movable laterally toward the spring, and stops to arrest the upward travel of said levers with said plunger to cause said levers to move said plates laterally tOWEIdySflld spring cover sides.

8. Spring cover applying apparatus compris-.

ing in combination spring straightening means, an air operated plunger device movable toward and away from the spring, levers pivoted to said plunger device and movable laterally toward the sides of the spring cover, stop devices pivotally connected with said levers, and stops adapted to be engaged by said stop devices at a predetermined elevation of said plunger device to actuate said levers to operate laterally upon the spring cover sides.

9. Spring cover applying apparatus comprising in combination, spring holding means, a holder for supporting a spring cover against the spring, cover bending devices for engaging the cover to bend it against the spring, and mechanism for elevating said devices into operative relation to the cover after the holder has engaged the cover.

10. Spring cover applying apparatus comprising in combinationsprifig holding means, a support for holding a spring cover against the under face of the spring, independent support elevating devices hinged to therespective ends of said support, and means for actuating said devices to move said support against the spring, said devices permitting said support to assume the angle of the under face or the spring.

11. Spring cover applying apparatus comprising in combination spring straightening means, devices for applying a cover to said spring, a trackway extending longitudinally of the spring, an air hammer carrier including a cylinder travelling on saidtrackway, a cylindrical air hammer operating in said cylinder and movable toward and away from said spring whereby the air hammer will remain in operative engagement with the spring as the same is moved longitudinally on said trackway, and a control device operable upon engagement with the work to cause the hammer to operate.

12. Spring cover applying apparatus comprising in combination spring straightening means, devices for applying a cover to said spring, a trackway extending longitudinally of the spring, an air hammer carrier including a cylinder travelling on said trackway, a cylindrical air hammer operating in said cylinder and movabletoward and away from .said spring, and an air trackway extending longitudinally of the spring,

an air hammer carrierincluding a cylinder travelling on said trackway, a cylindrical air hammer operating in said cylinder and movable toward and away from said spring, an air line connected to said cylinder for moving the hammer toward and holding it against the work whereby the air hammer will remain in operative engagement with the spring as the same is moved longitudinally on said trackway, and a device operated by the engagement of the hammer with the workto set the hammer in operation.

14. Spring cover applying apparatus comprising in combination spring straightening means, devices for applying a cover to said spring, a trackway extending longitudinally of the spring, an air hammer carrier including a cylinder travelling on said trackway, a cylindrical airhammer operating in said cylinder and movable toward and away from said spring, an air line connected to said cylinder for moving the hammer toward and holding it against thework whereby the air hammer will remain in operative engagement with the spring as the same is moved longitudinally on said trackway, a device operated by the engagement of the hammer with the work to set the hammer in operation, and a spring for raising said hammer upon the release of the air upon said cylinder.

15. Spring cover applying apparatus compris- 1 cover into engagement with the spring, and stop devices connected with said cover bending members and actuated by predetermined vertical travel of said members and independently of said spring for operating the latter to bend a cover against the spring.

16. Spring cover applying apparatus comprising in combination, a spring straightening plungerfor engaging an intermediate portion of a spring, spring holding arms pivoted on opposite sides of said plunger and adapted to engage the opposite ends of the spring and movable to accommodate varying spring lengths and to center the same on the plunger, and devices for applying a spring cover to a straightened spring carried by said holding arms. 

